Event ID 4776 - Log on account: none

[Dragon]

I have noticed alot of these errors in the security log of one of my DCs (called DC1).

 

"The computer attempted to validate the credentials for an account.

 

Authentication Package: MICROSOFT_AUTHENTICATION_PACKAGE_V1_0

Logon Account: None

Source Workstation: DC1

Error Code: 0xc0000064"

 

And every now and again the Domain\guest account gets locked out (even though its disabled). I unlock the account and within a minute it is locked out again.

 

I have tried running Network Monitor to capture where ever the log in request is from but I can't see anything thats causing it. It says the source is DC1 one but I assume that is because the log in request being made on that DC.

 

Any help would be appreciated.